imHistoConv

ubyte[] img_data =
[
    1,2,5,8,
    4,3,1,1
];

ubyte[] hi_x_data = [ 16, 9 ];
ubyte[] hi_y_data = [ 5, 5, 6, 9 ];

auto img = Image( ivec2(4,2), ElemInfo( 1, DataType.UBYTE ), img_data );
auto hi_x = Image( ivec!1(2), ElemInfo( 1, DataType.UBYTE ), hi_x_data );
auto hi_y = Image( ivec!1(4), ElemInfo( 1, DataType.UBYTE ), hi_y_data );

assert( imHistoConv(img,0) == hi_x );
assert( imHistoConv(img,1) == hi_y );